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Thread: 1994 K75 - Gasoline smell - Gasoline leaked when on side stand one time

  1. #1
    '94 K75 heejrbmw's Avatar
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    1994 K75 - Gasoline smell - Gasoline leaked when on side stand one time

    Usually I smell raw gasoline when I first start my engine. I don't smell anymore when I'm riding, or if I stop while the engine is warm, and restart, I don't smell. So, the only time I have noticed smell is when the engine is cold. Possibly related, or not, the other day I was getting ready to ride, started the engine, and remembered I left my sunglasses in the house. I put the k75 on the side stand and left the engine running. When I came back out - less than one minute later - I smelled gas very strong and saw gasoline pooling on the pavement. I turned the engine off, looked for a problem, but saw none immediately. I could not determine where the leak was, but there was fresh, wet gasoline behind the throttle body at the aft end. I restarted the engine on the center stand, and did not see a leak so I went for a ride with no issues. Also, related or not, I have noticed my gasoline mileage is not as good as it once was. My mileage is down around 40 to 43, but it use to be 50 to 52.

    I have spent several hours today looking for a leak and cannot find one. Any ideas would be greatly appreciated. I hate to put back together without finding the problem, if there is one. Thanks for any thoughts.
    Ed Evans - - Semper Fi
    '94 K75 '92 K75S
    "Always do more than expected." Coach Jerry Moore, ASU

  2. #2
    A bozo on the bus deilenberger's Avatar
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    If you still have original hoses on the bike - they are now almost 20 years old, and they owe you nothing. I'd start with the hoses. I'd also check the left rear lower corner of the tank. Despite being aluminum - they have been known to corrode through, usually in that corner. The cause is water in the tank. That's the lowest point and it tends to pool there, eventually causing corrosion and a leak. Usually rubbing your finger under the tank seam will reveal the leak.

    Other possible points might be - the gasket for the fuel level sender (and pump wiring feedthrough)..

    Whatever it is - I would be diligent in finding it and not be riding the bike until I did. K-bike-flambe' has happened to people and it generally doesn't end well.
    Don Eilenberger http://www.eilenberger.net
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  3. #3
    '94 K75 heejrbmw's Avatar
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    Quote Originally Posted by deilenberger View Post
    If you still have original hoses on the bike - they are now almost 20 years old.
    Don, thanks for the reply. I already had the gas tank off, so it was easy to check. It looks very good. No corrosion, no leaks. Looking at the hoses, they also look fairly good. (I don't have any idea if the previous owner ever replaced hoses.) Some have small, dry cracks at the clamp ends, but none are leaking. I will go ahead and replace them, but I'm not sure which ones I need to replace. It looks like only two of the ones I saw are fuel hoses.

    Here are the hoses I see:
    1) One formed hose from the gas tank goes to the fuel rail.
    2) The other formed hose from the gas tank goes to the pressure sensor.
    3) Another hose goes from the aft end of the fuel rail to the pressure sensor (looks like plain, unformed fuel line.)
    4) Another hose goes from the bottom of the pressure sensor to the injector (This is the one with the coiled wire around it, and looks like plain hose.)

    I'm not sure which of these carry fuel. (I think just (1) and (4).) Do all need to be replaced? When you, and others replace fuel lines, do you use OEM hoses, or do you use generic fuel lines?

    I have already replaced the fuel lines in the fuel tank.

    I also don't see any evidence of a fuel leak at the fuel pump or fuel level sender. However, under pressure that could be different.

    Thanks for your help.
    Ed
    Ed Evans - - Semper Fi
    '94 K75 '92 K75S
    "Always do more than expected." Coach Jerry Moore, ASU

  4. #4
    3 Red Bricks
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    1,2,&3 are all fuel hose.

    4 is a vacuum line.

    The fuel line should be fuel injection rated (high pressure 100psi).


    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
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  5. #5
    Curmudgeon At Large Bobmws's Avatar
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    Accumulator?

    There are 2 small tubes at the rear of your tank. One is a water drain from the small hole in the fuel fill under the cap, the other is the tank vent. Your bike should have a funnel type device (accumulator) in the frame just inder these two outlets, and a hose from the funnel down below the bike.
    It's possible if you had just filled the bike, especially if you have removed the filler neck to squeeze a bit more gas in, that the return line gas pushed fuel out the vent. Fairly common to see this when following a K leaving the gas station!
    Bob Weis
    '04 K12RS - Hannigan Hack
    www.earplugco.com

  6. #6
    '94 K75 heejrbmw's Avatar
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    Thanks Lee. I purchased fuel and vacuum line and will replace all. Thanks for straightening me out on which are fuel lines.

    Bob, thanks for your reply. I have removed the filler neck. I cannot remember how full the tank was when the fuel was leaking. It is possible that it was fairly full. I do have the accumulator in place with a hose that should put the overflow just in front of the rear tire. It seems that the fuel that pooled was forward of that, but now I don't remember for sure. With the bike on the side stand, I don't know if the fuel could have drained out of the overflow. Perhaps it could. However, this would not explain the raw fuel behind the throttle body.

    Ed
    Last edited by heejrbmw; 04-23-2013 at 01:11 AM.
    Ed Evans - - Semper Fi
    '94 K75 '92 K75S
    "Always do more than expected." Coach Jerry Moore, ASU

  7. #7
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    Behind the throttle body sounds like a leaky fuel return hose or FPR. I can't really think of a lot of ways for fuel to get to that area. Or conceivably a leaky fuel rail, I suppose.

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    Watching with interest on how you get to those fuel lines, I tried on my 1990 K75RT but gave up after becoming frustrated that I couldn't get past the air box removal to access them? If another way is available, I'll be interested in seeing it and may try again.
    MSF RiderCoach
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    Quote Originally Posted by edswope View Post
    Watching with interest on how you get to those fuel lines, I tried on my 1990 K75RT but gave up after becoming frustrated that I couldn't get past the air box removal to access them? If another way is available, I'll be interested in seeing it and may try again.
    On an RT, I BELIEVE you must remove the right side tupperware first. On other K75s, just remove the tank, then the upper air cleaner box, then the lower air cleaner box, and you're there.


    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
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    Quote Originally Posted by 98lee View Post
    On an RT, I BELIEVE you must remove the right side tupperware first. On other K75s, just remove the tank, then the upper air cleaner box, then the lower air cleaner box, and you're there.


    That's what I did on my 91 75RT. The lines on the regulator were rock hard and were loose. Right after I got the bike, I read on here where a guy had to bail off his 75RT when it caught fire.
    Ron

    91 K75RT ABS

  11. #11
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    Quote Originally Posted by roncooper View Post
    I read on here where a guy had to bail off his 75RT when it caught fire.
    I think they made a movie about that:

    GHOST RIDER LR copia.jpg



    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
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  12. #12
    Rally Rat Roc-Roc's Avatar
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    You need to check the fuel hose clamps. They do loosen over time. At first will only leak under pressure. Pay attention to hoses behind fuel rail.
    ROC-ROC
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  13. #13
    '94 K75 heejrbmw's Avatar
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    Quote Originally Posted by edswope View Post
    Watching with interest on how you get to those fuel lines, I tried on my 1990 K75RT but gave up after becoming frustrated that I couldn't get past the air box removal to access them? If another way is available, I'll be interested in seeing it and may try again.
    I'm happy to report that all fuel lines and vacuum lines are changed over to new ones, and there was absolutely no problem with getting to the areas needed to replace them. I'm only familiar with my K75 Standard. I understand that different fairings on other models present their own unique challenges. But, the Standard is relatively easy. I found no evidence of a fuel leak anywhere. The bike runs fine and I did not smell gasoline on a short ride, nor during a short idling period in the driveway. Everything appears to be OK. Time will tell.

    Thank all of your for helping and advising. I learned more about the bike and that is appreciated. No doubt I will find myself in positions where I will need to continue learning to be somewhat competent with repairs.

    Now I will just watch and make sure no leak appears, and also begin to troubleshoot the lower MPG the bike has experienced lately.

    Thanks!
    Ed Evans - - Semper Fi
    '94 K75 '92 K75S
    "Always do more than expected." Coach Jerry Moore, ASU

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